Scientists Use Nanoparticles to Deliver Anti-Cancer Drug

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US Research Team Use Nanoparticles to Deliver the Anti-Cancer Drug Paclitaxel into a Tumour

Nanoparticles made of a novel biodegradable polymer are able to deliver the water-insoluble anticancer drug paclitaxel successfully into the mass of a tumor, according to a new paper from a group led by Mansoor Amiji, Ph.D., at Northeastern University and Robert Langer, Ph.D., at the Massachusetts Institute of Technology. Based on this work, the investigators are moving to begin more detailed animal studies of how these nanoparticles behave in vivo.

Writing in the journal Pharmaceutical Research, the researchers discussed the second phase of their studies of nanoparticles that will release their contents when subjected to the abnormally acidic conditions inside a tumor cell in a mouse model of human cancer. The team’s earlier work with these nanoparticles appeared in September.

In the current study, the investigators once again used the biodegradable and biocompatible polymer known as PbAE to create pH-sensitive nanoparticles. For comparison, the investigators also made pH-stable nanoparticles from an FDA-approved polymer poly(caprolactone), also known as PCL. The investigators incorporated either paclitaxel, for tumor uptake studies, or a small molecule labeled with the radioisotope indium-111, for studying biodistribution. In the biodistribution studies, the research team found that nanoparticles made from the two polymers did not behave identically, with differences in both the rate at which the nanoparticles were taken up by the body and how the particles distributed throughout the body.

The subsequent tumor-uptake studies showed that far more paclitaxel ended up in tumors when delivered with PbAE nanoparticles compared to PCL nanoparticles. Within an hour of administration, for example, the tumor concentration of paclitaxel delivered using PbAE nanoparticles was more than double that obtained with the PCL nanoparticles. Benefits of the same magnitude were seen at five hours post-injection as well.

This work, supported by the National Cancer Institute, is detailed in a paper titled, “Poly(ethylene oxide)-modified poly(beta-amino ester) nanoparticles as a pH-sensitive system for tumor-targeted delivery of hydrophobic drugs: Part 2. In vivo distribution and tumor localization studies.” An abstract is available through PubMed.

Source: NCI Alliance for Nanotechnology in Cancer.

URL: http://nano.cancer.gov/news_center/nanotech_news_2005-11-28a.asp

This story was posted on 1 December 2005.